Using Hemolysis as a Novel Method for Assessment of Cytotoxicity and Blood Compatibility of Decellularized Heart Tissues

Innovation in ovary decellularization methods: Chemical and herbal detergents

The ovary provides an ideal environment for egg survival due to its distinct structure that directly contributes to the growth and maintenance of the follicle. The purpose of this study is to compare ovarian decellularization with herbal and chemical detergents. Sheep ovarian was used in this study. 1 % sodium dodecyl sulfate (SDS) as a chemical detergent and 1, 2.5, and 5 % Acanthophyllum (ACP) were used as herbal agents for decellularization. DNA content, histological characteristics, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), biocompatibility, antibacterial test, hemocompatibility, and scanning electron microscope (SEM) were investigated. The results showed the DNA content in decellularization scaffolds with 1 % SDS and 5 % ACP was reduced suitably. Also, histological observations confirmed this finding, and the nuclei were completely removed in these two groups. Disorganization of collagen fibers and tissue architecture was observed more in the SDS group than in the ACP group. No group reported cytotoxicity and the best blood compatibility in decellularization with herbal agents was reported. Protein bands are largely conserved in all methods. Higher antibacterial properties were observed in the decellularization technique with ACP. Decellularization with 5%ACP, in addition to being able to completely remove cells in the tissue, can help preserve the ultrastructure of the ovary. Therefore, this plant agent can be introduced as a decellularization method for studies in this field.

Injectable carboxymethyl chitosan/oxidized dextran hydrogels containing zoledronic acid modified strontium hydroxyapatite nanoparticles

Nanocomposite hydrogels have potential in bone regeneration due to the inorganic and polymeric material content. In this study, new types of nanocomposite hydrogels composed of zoledronic acid/strontium hydroxyapatite nanoparticles and carboxymethyl chitosan/oxidized dextran (CMC/OD) hydrogels were reported. Pure hydroxyapatite, 5%, 10% and 15% (w/w) strontium-substituted strontium hydroxyapatite nanoparticles were produced and then modified with zoledronic acid at ratios of 5% to 7.5% (w/w). These modified structures were then incorporated into CMC/OD hydrogels. Zoledronic acid modified strontium hydroxyapatite nanoparticles were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD). CMC/OD structures were investigated using Fourier Transform Infrared Analysis (FTIR), Scanning Electron Microscopy (SEM). The physical properties of the hydrogels were determined via degradation behavior and rheological measurements. Cell-material interactions were investigated in vitro. The results showed that the incorporation of hydroxyapatite nanoparticles into CMC would significantly improve the rheological properties. The addition of strontium to hydroxyapatite nanoparticles significantly enhanced cell proliferation. In addition, a significant increase in alkaline phosphatase (ALP) and calcium deposition was observed with the addition of zoledronic acid. In conclusion, the nanocomposite hydrogels of CMC/OD containing zoledronic acid modified strontium hydroxyapatite demonstrate potential for orthopedic and craniofacial applications due to their superior properties, including the ability to be easily injected into targeted areas, potent antibacterial activity that helps prevent infections and remarkable self-healing capabilities that promote tissue regeneration and repair.

Repair of critical-sized bone defects in rabbit femurs using graphitic carbon nitride (g-C3N4) and graphene oxide (GO) nanomaterials

Various biomaterials have been evaluated to enhance bone formation in critical-sized bone defects; however, the ideal scaffold is still missing. The objective of this study was to investigate the in vitro and in vivo regenerative capacity of graphitic carbon nitride (g-C₃N₄) and graphene oxide (GO) nanomaterials to stimulate critical-sized bone defect regeneration. The in vitro cytotoxicity and hemocompatibility of g-C₃N₄ and GO were evaluated, and their potential to induce the in vitro osteogenesis of human fetal osteoblast (hFOB) cells was assessed using qPCR. Then, bone defect in femoral condyles was created in rabbits and left empty as control or filled with either g-C₃N₄ or GO. The osteogenesis of the different implanted scaffolds was evaluated after 4, 8, and 12 weeks of surgery using X-ray, computed tomography (CT), macro/microscopic examinations, and qPCR analysis of osteocalcin (OC) and osteopontin (OP) expressions. Both materials displayed good cell viability and hemocompatibility with enhanced collagen type-I (Col-I), OC, and OP expressions of the hFOB cells. Compared to the control group, the bone healing process in g-C₃N₄ and GO groups was promoted in vivo. Moreover, complete healing of the bone defect was observed radiologically and grossly in g-C₃N₄ implanted group. Additionally, g-C₃N₄ implanted group showed higher percentages of osteoid tissue, mature collagen, biodegradation, and expressions of OC and OP. In conclusion, our results revealed that g-C₃N₄ and GO nanomaterials could induce osteogenesis in critical-sized bone defects.

Enhancement of critical-sized bone defect regeneration using UiO-66 nanomaterial in rabbit femurs

Background

Repair of large-sized bone defects is a challengeable obstacle in orthopedics and evoked the demand for the development of biomaterials that could induce bone repair in such defects. Recently, UiO-66 has emerged as an attractive metal–organic framework (MOF) nanostructure that is incorporated in biomedical applications due to its biocompatibility, porosity, and stability. In addition, its osteogenic properties have earned a great interest as a promising field of research. Thus, the UiO-66 was prepared in this study and assessed for its potential to stimulate and support osteogenesis in vitro and in vivo in a rabbit femoral condyle defect model. The nanomaterial was fabricated and characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM). Afterward, in vitro cytotoxicity and hemolysis assays were performed to investigate UiO-66 biocompatibility. Furthermore, the material in vitro capability to upregulate osteoblast marker genes was assessed using qPCR. Next, the in vivo new bone formation potential of the UiO-66 nanomaterial was evaluated after induction of bone defects in rabbit femoral condyles. These defects were left empty or filled with UiO-66 nanomaterial and monitored at weeks 4, 8, and 12 after bone defect induction using x-ray, computed tomography (CT), histological examinations, and qPCR analysis of osteocalcin (OC) and osteopontin (OP) expressions.

Results

The designed UiO-66 nanomaterial showed excellent cytocompatibility and hemocompatibility and stimulated the in vitro osteoblast functions. The in vivo osteogenesis was enhanced in the UiO-66 treated group compared to the control group, whereas evidence of healing of the treated bone defects was observed grossly and histologically. Interestingly, UiO-66 implanted defects displayed a significant osteoid tissue and collagen deposition compared to control defects. Moreover, the UiO-66 nanomaterial demonstrated the potential to upregulate OC and OP in vivo.

Conclusions

The UiO-66 nanomaterial implantation possesses a stimulatory impact on the healing process of critical-sized bone defects indicating that UiO-66 is a promising biomaterial for application in bone tissue engineering.

Kidney ECM Pregel Nanoarchitectonics for Microarrays to Accelerate Harvesting Gene-Edited Porcine Primary Monoclonal Spheres

One of the key steps of using CRISPR/Cas9 to obtain gene-edited cells used in generating gene-edited animals combined with somatic cell nuclear transplantation (SCNT) is to harvest monoclonal cells with genetic modifications. However, primary cells used as nuclear donors always grow slowly and fragile after a series of gene-editing operations. The extracellular matrix (ECM) formulated directly from different organs comprises complex proteins and growth factors that can improve and regulate the cellular functions of primary cells. Herein, sodium lauryl ether sulfate (SLES) detergent was first used to perfuse porcine kidney ECM, and the biological properties of the kidney ECM were optimized. Then, we used a porcine kidney ECM pregel to pattern the microarray and developed a novel strategy to shorten the time of obtaining gene-edited monoclonal cell spheroids with low damage in batches. Our results showed that the SLES-perfused porcine kidney ECM pregel displayed superior biological activities in releasing growth factors and promoting cell proliferation. Finally, combined with microarray technology, we quickly obtained monoclonal cells in good condition, and the cells used as nuclear donors to construct recombinant embryos showed a significantly higher success rate than those of the traditional method. We further successfully produced genetically edited pigs.

Decellularization of kidney tissue: comparison of sodium lauryl ether sulfate and sodium dodecyl sulfate for allotransplantation in rat

An automatic decellularization device was developed to perfuse and decellularize male rats' kidneys using both sodium lauryl ether sulfate (SLES) and sodium dodecyl sulfate (SDS) and to compare their efficacy in kidney decellularization and post-transplantation angiogenesis. Kidneys were perfused with either 1% SDS solution for 4 h or 1% SLES solution for 6 h. The decellularized scaffolds were stained with hematoxylin and eosin, periodic acid Schiff, Masson's trichrome, and Alcian blue to determine cell removal and glycogen, collagen, and glycosaminoglycan contents, respectively. Moreover, scanning electron microscopy was performed to evaluate the cell removal and preservation of microarchitecture of both SDS and SLES scaffolds. Additionally, DNA quantification assay was applied for all groups in order to measure residual DNA in the scaffolds and normal kidney. In order to demonstrate biocompatibility of the decellularized scaffolds, human umbilical cord mesenchymal stromal/stem cells (hUC-MSCs) were seeded on the scaffolds. In addition, the allotransplantation was performed in back muscle and angiogenesis was evaluated. Complete cell removal in both SLES and SDS groups was observed in scanning electron microscopy and DNA quantification assays. Moreover, the extracellular matrix (ECM) architecture of rat kidney in the SLES group was significantly preserved better than the SDS group. The hUC-MSCs were successfully migrated from the cell culture plate surface into the SDS and SLES decellularized scaffolds. The formation of blood vessels was observed in the kidney in both SLES and SDS decellularized kidneys. The better preservation of ECM than SDS introduces SLES as the solvent of choice for kidney decellularization.

Decellularization of porcine whole lung to obtain a clinical-scale bioengineered scaffold

Whole-organ engineering is emerging as an alternative source for xenotransplantation in end-stage diseases. Utilization of decellularized whole lung scaffolds created by detergent perfusion is an effective strategy for organ replacement. In the current study, we attempted to decellularize porcine whole lungs to generate an optimal and reproducible decellularized matrix for future clinical use. Porcine whole lungs were decellularized via perfusion of various detergents (sodium dodecyl sulfate (SDS)/Triton X-100, sodium lauryl ether sulfate (SLES)/Triton X-100, dextrose/SDS/Triton X-100 and dextrose/SLES/Triton X-100) through the pulmonary artery and bronchus of the lung. The decellularized scaffolds were evaluated for decellularization efficiency, extracellular matrix (ECM) component preservation, xenoantigen removal and compatibility. The resulting lung scaffolds obtained from treatment with the dextrose/SLES/Triton X-100 cocktail showed minimal residual cellular components and xenoantigens, including DNA and protein, and good preservation of ECM composition. Evaluation of the porcine lung ECM by specific staining and immunofluorescence confirmed that the three-dimensional ultrastructure of the ECM was noticeably preserved in the SLES-treated groups. In addition, the decellularized lung scaffolds originating from the dextrose/SLES/Triton X-100 cocktail supported cell adhesion and growth. In summary, the novel detergent SLES alleviated the damage to retain a better-preserved ECM than SDS. Sequential Triton X-100 perfusion eliminated SLES. Moreover, performing dextrose perfusion in advance further protected scaffold components, especially collagen. We developed an optimal dextrose/SLES/Triton X-100 cocktail method that can be used for the decellularization of porcine whole lung to obtain a clinical-scale bioengineered scaffold.

A novel decellularization method to produce brain scaffolds

Scaffolds composed of extracellular matrix (ECM) can assist tissue remodeling and repair following injury. The ECM is a complex biomaterial composed of proteins, glycoproteins, proteoglycans, and glycosaminoglycans, secreted by cells. The ECM contains fundamental biological cues that modulate cell behavior and serves as a structural scaffold for cell adhesion and growth. For clinical applications, where immune rejection is a constraint, ECM can be processed using decellularization methods intended to remove cells and donor antigens from tissue or organs, while preserving native biological cues essential for cell growth and differentiation. Recent studies show bioengineered organs composed by a combination of a diversity of materials and stem cells as a possibility of new therapeutic strategies to treat diseases that affect different tissues and organs, including the central nervous system (CNS). Nevertheless, the methodologies currently described for brain decellularization involve the use of several chemical reagents with many steps that ultimately limit the process of organ or tissue recellularization. Here, we describe for the first time a fast and straightforward method for complete decellularization of mice brain by the combination of rapid freezing and thawing following the use of only one detergent (Sodium dodecyl sulfate (SDS)). Our data show that using the protocol we describe here, the brain was entirely decellularized, while still maintaining ECM components that are essential for cell survival on the scaffold. Our results also show the cell-loading of the decellularized brain matrix with Neuro2a cells, which were identified by immunohistochemistry in their undifferentiated form. We conclude that this novel and simple method for brain decellularization can be used as a scaffold for cell-loading.

Decellularized extracellular matrix-rich hydrogel-silver nanoparticle mixture as a potential treatment for acute liver failure model

Acute liver failure (ALF) occurs due to severe liver damage that triggers rapid loss of normal liver function. Here, we investigate the usefulness of an injectable liver extracellular matrix (LECM)-rich hydrogel generated from an optimized decellularization protocol incorporated with silver nanoparticles (AgNPs) as a promising therapy for ALF. First, we optimized a non-destructive protocol for rat liver decellularization to obtain ECM-rich well-preserved scaffold. Then, LECM hydrogel generated from two commonly used decellularization protocols were compared by LECM hydrogel obtained from our optimized protocol. The ALF model was induced by an intraperitoneal (IP) thioacetamide (TAA) injection followed by the IP injection of LECM hydrogel, collagen-AgNP mixture, or LECM hydrogel-AgNP mixture. LECM-rich scaffold and hydrogel were successfully obtained using our optimized decellularization protocol. Use of the LECM hydrogel-AgNP mixture to treat TAA-induced ALF greatly improved liver injury and histological liver regeneration. Interleukin-6 and transforming growth factor-beta expressions were significantly reduced, while albumin, hepatocyte growth factor, and Ki67-positive cells were highly expressed. Moreover, aspartate transaminase and alanine transaminase plasma levels and liver homogenate nitric oxide level were significantly lowered. In conclusion, the LECM hydrogel-AgNP mixture has potential efficient therapeutic and regenerative effects on TAA-induced liver injury.

In vitro and in vivo investigation of PLA/PCL scaffold coated with metformin-loaded gelatin nanocarriers in regeneration of critical-sized bone defects

Large bone defects constitute a major challenge in bone tissue engineering and usually fail to heal due to the incomplete differentiation of recruited mesenchymal stem cells (MSCs) into osteogenic precursor cells. As previously proposed, metformin (MET) induces differentiation of MSCs into osteoblastic lineages in vitro. We fabricated a Poly (lactic acid) and Polycaprolactone (PLA/PCL) scaffold to deliver metformin loaded gelatin nanocarriers (MET/GNs) to critical-sized calvarial bone defects in a rat model. The scaffolds were evaluated regarding their morphology, porosity, contact angle, degradation rate, blood compatibility, biomechanical, cell viability and their osteogenic differentiation. In animal study, the defects were filled with autograft, scaffolds and a group was left empty. qRT-PCR analyses showed the expression level of osteogenic and angiogenic markers considerably increased in MET/GNs-PLA/PCL. The in vivo results showed that MET/GNs-PLA/PCL improved bone ingrowth, angiogenesis and defect reconstruction. Our results represent the applicability of MET/GNs-PLA/PCL for successful bone regeneration.

Biocompatibility and hemocompatibility of efficiently decellularized whole porcine kidney for tissue engineering

Whole kidney decellularization is a promising approach in regenerative medicine for engineering a functional organ. The reaction of the potential host depends on the biocompatibility of these decellularized constructs. Despite the proven ability of decellularized kidney scaffolds to guide cell attachment and growth, little is known about biocompatibility and hemocompatibility of these scaffolds. Our aim is to prepare decellularized kidneys of a clinically relevant size and evaluate its biocompatibility and hemocompatibility. Porcine kidneys were cannulated via the renal artery, and then perfused with 0.1% sodium dodecyl sulfate solution. Hematoxylin and eosin as well as DAPI staining confirmed cellular clearance from native kidneys in addition to preservation of the microstructure. SEM confirmed the absence of any cellular content within the scaffold, which is maintained in a well-organized 3D architecture. Decellularized kidneys retained the intact renal vasculature upon examination with contrast radiography. The essential structural extracellular matrix molecules were well-preserved. Scaffolds were susceptible to enzymatic degradation upon collagenase treatment. Scaffolds showed a good hemocompatibility when exposed to porcine blood. Decellularization was efficient to remove 97.7% of DNA from native kidneys in addition to the immunogenic and pathogenic antigens. Scaffolds did not induce the human immune response in vitro. Decellularized kidneys were non-cytotoxic to pig kidney cells (PKs). PKs were able to grow and proliferate within the decellularized renal scaffolds with maintaining a higher function than cells grown as monolayers. Thus, we have developed a rapid decellularization technique for generating biocompatible kidney scaffolds that represents a step toward development of a transplantable organ. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2034-2047, 2018.